綁定DataGrid列DataTemplate中以附加屬性

Question

我想定製 DataGridColumnHeader顯示多個文本字段，而不是
僅表示 DataGridColumn.Header酒店所提供的標題文字。
如果我沒有錯過任何東西，我只需創建一個 DataTemplate並綁定到父對象的屬性
。這適用於 DataGridColumn.Header屬性，但
對附加屬性的綁定失敗。

爲了完整起見，執行附加屬性：

public static class CustomHeader 
{ 
    public static string GetUnit(DependencyObject obj) { return (string)obj.GetValue(UnitProperty); } 
    public static void SetUnit(DependencyObject obj, string value) { obj.SetValue(UnitProperty, value); } 

    public static readonly DependencyProperty UnitProperty = DependencyProperty.RegisterAttached(
     "Unit", typeof(string), typeof(CustomHeader), new FrameworkPropertyMetadata(null)); 
} 

在XAML的標記使用方法：

<DataGrid x:Name="tObjectDataGrid" Margin="10,50,10,10" 
        AutoGenerateColumns="False" EnableRowVirtualization="True" 
        ItemsSource="{Binding ObjectList}" 
        RowDetailsVisibilityMode="VisibleWhenSelected" > 
    <DataGrid.Resources> 
    <DataTemplate x:Key="CustomHeaderTemplate"> 
     <StackPanel> 
     <TextBlock Text="{Binding}" /> 
     <TextBlock Text="{Binding Path=(cust:CustomHeader.Unit)}" /> <-- attached binding doesn't work :( 
     </StackPanel> 
    </DataTemplate> 
    </DataGrid.Resources> 

    <DataGrid.Columns> 
    <DataGridTextColumn x:Name="SpeedColumn" 
         Width="1*" 
         Binding="{Binding Speed}" 
         Header="Speed" 
         HeaderTemplate="{StaticResource CustomHeaderTemplate}" 
         cust:CustomHeader.Unit="[m/s]" /> 
    </DataGrid.Columns> 
</DataGrid> 

我真的很感激任何意見或網絡鏈接來闡明我缺少什麼這裏。 在此先感謝。

Answer 1

您應該使用多值轉換器（msdn）。

XAML：

<DataGrid x:Name="tObjectDataGrid" Margin="10,50,10,10" 
      AutoGenerateColumns="False" EnableRowVirtualization="True" 
      ItemsSource="{Binding ObjectList}" 
      RowDetailsVisibilityMode="VisibleWhenSelected" > 
    <DataGrid.Resources> 
     <cust:UnitConverter x:Key="unitCon" /> 
     <DataTemplate x:Key="CustomHeaderTemplate"> 
      <StackPanel> 
       <TextBlock Text="{Binding}" /> 
       <TextBlock> 
        <TextBlock.Text> 
         <MultiBinding Converter="{StaticResource unitCon}"> 
          <Binding Path="Columns" RelativeSource="{RelativeSource Mode=FindAncestor, AncestorType=DataGrid}" /> 
          <Binding Path="." /> 
         </MultiBinding> 
        </TextBlock.Text> 
       </TextBlock> 
      </StackPanel> 
     </DataTemplate> 
    </DataGrid.Resources> 

    <DataGrid.Columns> 
     <DataGridTextColumn x:Name="SpeedColumn" 
       Width="1*" 
       Binding="{Binding Speed}" 
       Header="Speed" 
       HeaderTemplate="{StaticResource CustomHeaderTemplate}" 
       cust:CustomHeader.Unit="[m/s]" /> 

     <DataGridTextColumn x:Name="SpeedColumn2" 
       Width="1*" 
       Binding="{Binding Speed2}" 
       Header="Speed2" 
       HeaderTemplate="{StaticResource CustomHeaderTemplate}" 
       cust:CustomHeader.Unit="[km/h]" /> 
    </DataGrid.Columns> 
</DataGrid> 

代碼隱藏：

public class UnitConverter : IMultiValueConverter 
{ 
    public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture) 
    { 
     string result = null; 

     ObservableCollection<DataGridColumn> columns = values[0] as ObservableCollection<DataGridColumn>; 
     string headerName = values[1].ToString(); 

     var coll = columns.Where(x => x.Header.ToString() == headerName).FirstOrDefault(); 

     if (coll != null) 
      result = CustomHeader.GetUnit(coll); 

     return result; 
    } 

    public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture) 
    { 
     throw new NotImplementedException(); 
    } 
} 

我認爲更好的解決方案將是創建新類如HeaderData之後，你可以在XAML中創建它的實例，並結合這個班。

例子：

類持有頭數據：

class HeaderData 
{ 
    public string Name { get; set; } 
    public string Unit { get; set; } 
} 

XAML代碼：

<DataGrid x:Name="tObjectDataGrid" Margin="10,50,10,10" 
      AutoGenerateColumns="False" EnableRowVirtualization="True" 
      ItemsSource="{Binding ObjectList}" 
      RowDetailsVisibilityMode="VisibleWhenSelected" > 
    <DataGrid.Resources> 
     <DataTemplate x:Key="CustomHeaderTemplate"> 
      <StackPanel> 
       <TextBlock Text="{Binding Name}" /> 
       <TextBlock Text="{Binding Unit}" /> 
      </StackPanel> 
     </DataTemplate> 
    </DataGrid.Resources> 
    <DataGrid.Columns> 
     <DataGridTextColumn x:Name="SpeedColumn" 
         Width="1*" 
         Binding="{Binding Speed}"         
         HeaderTemplate="{StaticResource CustomHeaderTemplate}">    
      <DataGridTextColumn.Header> 
       <cust:HeaderData Name="Speed" Unit="[m/s]" /> 
      </DataGridTextColumn.Header> 
     </DataGridTextColumn> 
     <DataGridTextColumn x:Name="SpeedColumn2" 
         Width="1*" 
         Binding="{Binding Speed2}"         
         HeaderTemplate="{StaticResource CustomHeaderTemplate}"> 
      <DataGridTextColumn.Header> 
       <cust:HeaderData Name="Speed2" Unit="[km/h]" /> 
      </DataGridTextColumn.Header> 
     </DataGridTextColumn> 
    </DataGrid.Columns> 
</DataGrid> 

Answer 2

乍一看，你的代碼是正常的，應該工作。但是當您的依賴屬性設置爲DataGridTextColumn,SetUnit未調用且變量Unit值NULL。我試圖在Window分配附加依賴屬性的值（因爲它連接，你可以在任何地方設置它的值）在這種情況下，必須努力：

<Window x:Class="DataGridAttachedHelp.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:local="clr-namespace:DataGridAttachedHelp" 
    local:CustomHeader.Unit="[m/s]" 
    Name="MyWindow" 
    Title="MainWindow" Height="350" Width="525" 
    WindowStartupLocation="CenterScreen"> 

<Grid> 
    <DataGrid x:Name="tObjectDataGrid" Margin="10,50,10,10" 
       AutoGenerateColumns="False" EnableRowVirtualization="True"      
       RowDetailsVisibilityMode="VisibleWhenSelected" > 

     <DataGrid.Resources> 
      <DataTemplate x:Key="CustomHeaderTemplate"> 
       <StackPanel> 
        <TextBlock Text="{Binding}" /> 
        <TextBlock Text="{Binding Path=(local:CustomHeader.Unit), ElementName=MyWindow}" /> 
       </StackPanel> 
      </DataTemplate> 
     </DataGrid.Resources> 

     <DataGrid.Columns> 
      <DataGridTextColumn x:Name="SpeedColumn" Width="1*" Binding="{Binding Speed}" Header="Speed" 
        HeaderTemplate="{StaticResource CustomHeaderTemplate}" /> 
     </DataGrid.Columns> 
    </DataGrid>  
</Grid> 
</Window> 

在你的情況下，物業沒有工作，因爲它是必要的以指示屬性的來源，例如：ElementName,Source。因此，只需在參數ElementName加DataGridTextColumn名稱：

<TextBlock Text="{Binding Path=(local:CustomHeader.Unit), ElementName=SpeedColumn}" />